Improvement in joints of folding rules



. UNITED STATES PATENT OFFICE.

JUSTUS A. TRAUT, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TO THE STANLEY RULE AND LEVEL COMPANY, OF SAME PLACE.

IMPROVEMENT IN JOINTS OF FOLDING RULES.

Specification forming part of Letters Patent No. 48,327, dated June 20, 1865.

To all 'whom it may concern Beit known that I, JUsTUs A. TRAUT, of

New Britain, county of Hartford, and State of Connecticut, have invented certain new and useful Improvements in Foldltules; and I do hereby declare that the same is `described and represented in the following specification and drawings, and to enable others` skilled iu the art to make and use the same, I will proceed to describe its construction by referring to the drawings and letters of reference marked therej The nature of this improvement will be uit derstood from the specication and drawings. The object desired to be obtained thereby is to secure a proper rigidness to the joints, so as to hold open in a straight line. In the common rules now in use, after they have been used a little time the joints become loose, so as to render it necessary to set up the joint by hammering the rivet or fulcrum-pin in order to tighten the joint. By this improvement it is believed that the difficulty will be entirely obviated.

In the accompanying drawings, Figure 1 shows a section of a rule or joint as constructed under this improvement, and showing the device protruding, by means of which the rule is set or rendered more rigid than in the common rules. Fig. 2 shows ajoint opened to about a right angle to show the protrusion of a spring on the outside of the joint. Fig. 3 is a sect-ion cut through the center of the rule to show the device in detail.

aJ is ametallic joint. b shows the wood to which the joint is fitted, both of which are made in the usual way. In the center piece, a', of the joint is cut one or more slits, c, diverging in about a right-angle direction from a point in the circle of the joint nearly in line of the inside edge ofthe rule. Into these slits Iplace a metallic spring, d, the shape of which will be understood by reference to the drawings. This spring should be made about the same in width with the thickness of the center piece, a', ofthejointin which it is placed.

e is a curved piece of metal secured by pins i, or other proper means, to the wood-work, so as to fit closely up to the outer edge of the center portion, a,.of the joint, 'so that the protrudin g surface of the sprin g d will work against the surface of said curved piece e. These springs may be made more or less tenacious, as desirable. By this arrangement the rule may be open and for use, and retain its straight or rigid position.

I am aware that other forms of springs may be used to accomplish the same purpose without changingthe principle of myimprovement.

I believe I have thus shown the nature, construction, and advantage of my improvement, so as to enable others skilled in the art to make the same therefrom.

What I claim therefore, and desire to secure by Letters Patent, is

1. The slit o in the center piece, a', of the joint a, for the purpose of receiving a device for producing tension or rigidness, substantially as and for the purpose described.

2. The employment of a metal piece, d, or its equivalent, placed in the slits of the joint a, substantially as `and for the purpose described.

` J USTUS A. TRAUI. [1.. s.]

Witnesses:

R. S. PORTER,

ALFRED ANDREWZ. 

